Howdy Everyone,

I just bought my first ford truck. It's an '85 F250, supercab, longbed with the 6.9 Diesel. I'm okay with a wrench, but this thing is my first diesel truck, and so I'm a bit lost in some things.

The glow plug light does not come on at start up. After verifying the light is good, followed by the truck not starting under 50 degrees without being plugged in, I think the glow plug system is not functioning. I haven't bought a manual yet, and need this fixed. Can anyone tell me where the Glow Plug terminal is located? I'm trying to find what part of the system isn't hooked up, and have come up empty when tracing wires. Like I said, I just bought this thing, and I'm hoping it could be an easy fix.

Any help y'all can give me would be appreciated. I hope to get a manual in the next couple of days, but until then, I'd love to be able to be working on it. Any help would be appreciated!

Thanks in advance! I look forward to participating in this forum!

Tim

 

howdy, and welcome to FTE. you have definitely found the best place to get your truck running like new again. hang on a spell ,and someone will be here that knows more about your 85 glow system to help you. our resident moderator, Dave, will eventually show up and walk you through the system. i don't think there is anything about those 6.9 trucks he don't know.

 

Thanks so much. This place looks to be a gold mine of knowledge. I've got a lot to do to the truck even though it runs. The injectors look like they were redone really cheap (fuel line with screw clamps) and they leak all over the engine. Upside ... the top of that engine is CLEAN! Thanks again and I'll see if I can't add a voice (albeit a pretty ignorant one for now).

 

remember,we were all uneducated at one time or another.
the difference is whether we want to stay uneducated or
learn, and then help others.

and there are no stupid questions except for the ones you do not ask. we may tease you a bit, but sooner or later you will have some knowledge we will need, then you can be the teacher.

 

Tim I dont think there is a question that can be asked on here that someone cant give you a good answer to. A lot of the time your post may go on a WILD tangent for a while, but you will get an answer and probably more than a few good laughs on the way.

 

Those clamps are probably on the return lines between the injectors. You'd be doing yourself a HUGE favor, if you replaced the return line hoses, clamps, caps and o-rings asap. They are a well-known place for air to get into your fuel system. I bought mine from associated diesel a few months ago and they were only $25. Now they are $29. Here is a link, to the kit you need LINK

Oh.... Welcome to FTE!

Gary

 

Thanks for the link! That looks like EXACTLY what I need! On the right side of the engine ... there is a 2 inch long piece of tubing with a screw in the end. I guess that was his way of sealing the end. Unfortunately, it leaks bad now! I'm usually pretty fond of southern engineering ... but when it's on fuel lines, I typically don't.

Thanks Gary!

 

As far as your glow plug system goes, Your truck probably has the old-style GP controller and they were known to fail in the "On" position. This controller is located at the rear of the engine and is screwed into the driver's side head. From 1987 on, they used a solid state GP controller and they have proven VERY reliable. Once you get all your GP's straightened out, I would suggest you going with the solid state system.

An easy test, to see if your GP's are still good, is to use a test light. Unplug the wires from the top of the GP's and use a test light that is hooked to the positive terminal of one of your batteries. Make sure you touch only the tip of the GP, since the base is a ground. If the test light does light up, your GP is probably good.

Another word of warning.... If you search the threads for glow plug posts, you will find that Motorcraft(Ford)/Beru glow plugs are the ONLY ones recommended. Trust me, when I say that this recommendation comes out of the experiences of many users here. Champion and Autolite GP's have the worst reputation, for lasting only a few weeks at most.

Gary

 

The return lines go between all the injectors, the fuel filter head and the injection pump. It is a closed system and there should be NO screws in the end of any of them. In my opinion, you should fix the return lines, before you do anything else.

Gary

 

Thanks, I think you pointed me at the right place to look. I know there is a switch right behind the passenger side battery that has one of the orange wires with green dots (I think that is the glow plug line). Is this the Glow Plug Switch?

I did see something at the rear of the driver side engine that looked like it was screwed into the head. Is there a way to test the controller? or is it just a part that you replace?

I know that once I get my manual, this will all be clear as mud, so thanks for teaching me what I'm doing in the mean time!

 

It's that big a deal eh? (besides the obvious thought that the pools of diesel fuel around the glow plugs could be dangerous). I think you are right.

Right off of the front most driver-side injector, there is a 2 inch piece of tube that extends forward (towards the radiator) with a screw in it. The other side looks like it has an appropriate cap with a clamp. Gotta love that southern engineering.

 

Here is a write-up that I got from this web page. It is very useful info!

Return line refit

Obtain new injector caps, hoses and clamps. These may be in the form of individual parts purchased at a Ford or IH dealer, or an injector servicing kit, such as those sold by DIS, DPS-Performance, MWFI and other online sources. If re-using existing injectors, replace all the O-rings that were on them. Keep in mind that the caps sold for use on 6.9 and 7.3 engines are different, in that the two engines used different size hose, and consequently different size nipples on the caps. It is possible to use either size on either engine, however for the purposes of this article, it is advisable to replace like kind for like kind, and keep the routing of the hoses the same. In most cases the hose is not pre-cut to length, and comes in a spool. You will need to cut the hose to the right length to install it. Use the old hoses as a guide to cutting them to the right length. Apply some petroleum jelly to the O rings, and press the new fuel return line caps onto the injectors. The caps will seat with a good “click”. You will know they are on properly when you see that the top of the cap is seated on the shoulder of the injector, below the injection line connection threads. Under no circumstance should you find that the nut on the injection line is pushing down on the cap when you go to install the injection lines. Orient the caps in such a way that the cap barbs point towards each other. Once all the caps are on, take each length of new hose that you have prepared, and place a clamp on the hose an inch or two from the ends. Push the hose onto the return line cap barbs, and slide the clamp towards the end of the hose, seating it on the hose close to the end for maximum grip. The hoses between injectors should be straight and not bowed. If they are bowed, they are either too long, or not on the return line cap barbs fully. If the hose is too short, it will not cover enough of the barb to seal reliably. Ideally, the end of each hose length should all but touch the return line cap body. Once all the lines are installed, review the routing. Be sure that the fuel filter head and injection pump both have returns and that all returns can make it back to the fuel tank. A common mistake may be to not connect the passenger side bank with the drivers side bank in some fashion. Review all hose connections to make sure the spring clamps are properly seated, and ensure that no return line caps have come off of their injectors.

 

If I'm not mistaken, that line should go to the return from the injection pump. The passenger side should have a line that goes from the first cap, to the fuel filter head.

Gary

 

ttexastim,
Welcome to FTE and the IDI diesel forum.

Your first step is check the glow plugs to find out if any are burnt out.
The test light is a good easy fast way to check for dead plugs.

The glow plug controller is screwed down on the inside rear of the drivers side head and goes into the coolant jacket.
Given the controller is around 100 dollars, and they are slightly famous for breaking off when you try to remove them, most people just convert to manual glow plugs when it dies.
The decieding factor is usually who drives the truck.
If the owner is the only driver, manual plugs are great.
If other people drive it, well counting off 10 seconds seems to be a challange for some reason.

The second part of the system is the glow plug relay, mounted behind the passanger side battery down on the inner fender liner.



Be aware the engine was out of my truck when I took that picture, there are two orange wires with white stripes that are also supposed to be on the left big terminal.

The purple wire is the trigger wire from the glow plug controller.

To go manual, run a wire from that terminal to a momentary switch in the dash.
Get power from the fuse panel inside, I preffer a switch fuse that only has power when the key is on, but that is not an absolute requirement.
That power runs to the other terminal of the momentary switch.

The momentary switch is a very good idea, spring loaded to off so it can not be switch on and left on.

You are done with the conversion.

Now another check of the system is in order while you are under the hood.



Look for the connector circled in red with the two large orange wires on the bottom.
The large gauge orange wires are power to the glow plugs.
That connector is famous for melting and loosing connection, which means full power (200 amps) is not making it to the glow plugs.

If the connector loks like it has been hot or is deformed, or if it will not come apart, chances are it is in bad shape.
Cut the orange wires as close to the connnector as you can, which will let you splice them back together outside the connector.

Operation,
Key on.
Push and hold the switch on for 10 seconds.
Start the engine.

 

if you have diesel on your motor your return lines are leaking.if fuel is coming out air is going in.air in a fuel line is very bad it causes really hard starts or maybe even a no-start situation.the kit is cheap i would buy one asap.its a common issue so there is a wealth of info on it.kinda surprised nobody really jumped on that one.